Ask yourself how am I using the monolith? Particle whip? Portal? Those are the usual tricks. I use it to project force on the table, and as part of the cornerstone of my three “unkillables”- monolith, Deceiver, Destroyer Lord. What it takes to put these guys down is a lot of commitment, more then most builds can handle if you are not ready for what I am going to do with them. This gives my other units a little more operating room. The monolith and my destroyer lord are the synergy- from shooting you can’t put down my destroyer lord and deny his WBB roll + he has a phylactery and failing that I portal him for another chance. Stringing combos like this is where Necrons are right now.